This invention relates to bases for high speed routers, either upright in hand held position or inverted and suspended in a router table, and specifically to more precise control of placement of the router cutting tool.
In presenting the specification and claims it is felt that someone skilled in the art is familiar with the router related terms such as router fence, workpiece and others, therefore these items have not been shown in the formal drawings although they may be referenced in the specification and claims.
The modern high speed router is generally used in the cutting of grooves, slots, step cuts, or some decorative edge cuts. Producing these different cuts requires very careful measuring of the distance between center of the installed cutting tool and the edge of the router base that will abut a guiding device. These measurements must be transferred to either the guiding device, usually called a fence and the layout or cutting line of the workpiece. This fence may be a guide clamped to the workpiece, a router table adjustable fence, or a fence capable of being attached to the router body. All of these devices leave room for error and the devices clamped to the router are usually limited in capacity to reach the inner portions of larger wood sheets such as plywood panels. All of them usually require a test cut for accuracy before addressing the actual workpiece and none give some indication of the actual cutting tool margins.
Prior art leaves much to be desired in precisely placing the router cutting tool to the desired cutting line accurately. U.S. Pat. No. 4,921,023 to Pempek (1990) does show some capability of placing the cutting tool on the cutting line, but does not precisely show cutting tool margins and is limited to about 6 inches of adjustability in side movement. This would not be usable in wider sheets such as plywood. U.S. Pat. No. 5,299,609 to Wedler (1994) is a clamped on fence device with very limited edge to cut capability. All require very careful measuring and remeasuring, and usually a test cut for accuracy.
The principal object of this invention is to provide a router base device for precisely and accurately aligning the diameter margins of the installed router cutting tool to the layout or actual cutting line of the workpiece and to precisely guide the router according to this alignment.
A further object is to provide built in measuring capabilities for moving the router on the base to right or left in order to enlarge the existing cut without the necessity of changing cutting tools.
A further object is to make this device invertable and mountable in a router table while retaining the alignment and measuring capabilities.
It is also the object of this invention to make this device easy to operate, lightweight and not cumbersome, and retaining the portability of the router.
A further object of this invention is simplicity of operation such that a skilled or unskilled person can produce the grooves, slots, dadoes, and other cuts within the router capability with precision and accuracy in a timely manner.
These and other objects are addressed and accomplished in the present invention wherein the baseplate is provided with a cutout portion on the front edge for containment and engagement of a pair of indicator blocks, each with an inner primary alignment indicator and a plurality of secondary measuring indicators. Rearward projections of indicator blocks ride on upper surface of baseplate and are contained by an elongated side to side slot for passage through of a thumbscrew securing them to the baseplate in a changeable predetermined position.
Alignment of primary alignment indicators to a scrapwood reference cut of the installed cutting tool shows diameter margins of the cutting tool, and when these indicators are referenced to the layout or cutting line of the workpiece and a guiding device abutted to the edge of the routers guide baseplate a precise and accurate cut must follow.
Inverting the router suspended by the baseplate in a router table requires a minor change in procedure. Reference cuts are made with scrapwood against router table fence and primary alignment indicators on baseplate are secured to reference margins. As the router is secured to the router table and immovable the workpiece layout lines are aligned to the alignment indicators on the bottom of the indicator blocks which are now on top in the inverted position and the router table fence abutted to the workpiece.